iceman231

hi just wondering if you can state the step by step procedure to do a leak down test on a engine

joe_bocc

I'm not exactly sure if this is right. If anyone knows better please correct me.

Put the piston in the cylinder you are testing at TDC.
Attach the spark plug attachment to the compressor hose.
Remove the spark plug.
Screw the spark plug attachment into the spark plug hole.
Turn on the compressor and fill the cylinder with compressed air.
Listen through the intake, the oil cap, and the exhaust (muffler).

If hissing comes out of your intake, your intakevalves are not closing properly.
If hissing comes out of your oil fill hole, your rings are bad.
If hissing comes out your muffler, your exhaust valves are not closing properly

Stewie

That's good Joe.

I just wanna give a little tip. You wont be able to hear 12% or so past the exhaust valves by listening to the muffler. So, to hear moderate leaks past the exhaust valves, you have to be close to the cylinder head. For example, remove the cat and listen just after the A-pipe.

JimBlake

Dont forget to lock the crankshaft from turning. When you pressurize the cylinder, it's going to try to turn if you have it just slightly off TDC.